全文获取类型
收费全文 | 183130篇 |
免费 | 14494篇 |
国内免费 | 7526篇 |
专业分类
电工技术 | 10313篇 |
技术理论 | 17篇 |
综合类 | 11421篇 |
化学工业 | 31479篇 |
金属工艺 | 9935篇 |
机械仪表 | 11348篇 |
建筑科学 | 15292篇 |
矿业工程 | 5347篇 |
能源动力 | 5406篇 |
轻工业 | 11600篇 |
水利工程 | 3138篇 |
石油天然气 | 11342篇 |
武器工业 | 1391篇 |
无线电 | 21000篇 |
一般工业技术 | 22278篇 |
冶金工业 | 8905篇 |
原子能技术 | 2000篇 |
自动化技术 | 22938篇 |
出版年
2024年 | 775篇 |
2023年 | 2969篇 |
2022年 | 5148篇 |
2021年 | 7085篇 |
2020年 | 5515篇 |
2019年 | 4680篇 |
2018年 | 5096篇 |
2017年 | 5922篇 |
2016年 | 5115篇 |
2015年 | 7076篇 |
2014年 | 8708篇 |
2013年 | 10387篇 |
2012年 | 11343篇 |
2011年 | 12158篇 |
2010年 | 10608篇 |
2009年 | 10097篇 |
2008年 | 9847篇 |
2007年 | 9487篇 |
2006年 | 9955篇 |
2005年 | 8653篇 |
2004年 | 5942篇 |
2003年 | 5184篇 |
2002年 | 4912篇 |
2001年 | 4484篇 |
2000年 | 4605篇 |
1999年 | 5071篇 |
1998年 | 4384篇 |
1997年 | 3682篇 |
1996年 | 3431篇 |
1995年 | 2849篇 |
1994年 | 2449篇 |
1993年 | 1728篇 |
1992年 | 1383篇 |
1991年 | 1098篇 |
1990年 | 814篇 |
1989年 | 688篇 |
1988年 | 580篇 |
1987年 | 387篇 |
1986年 | 267篇 |
1985年 | 172篇 |
1984年 | 100篇 |
1983年 | 82篇 |
1982年 | 102篇 |
1981年 | 57篇 |
1980年 | 47篇 |
1979年 | 13篇 |
1978年 | 4篇 |
1965年 | 3篇 |
1959年 | 6篇 |
1951年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Anumberoflanthanideternarycomplexescon tainingheterocyclicamineshavebeenreportedsince1960 [1] .Inrecentyearsmuchattentionhasbeenpaidtoquaternarycomplexesoflanthanidesbecauseofin terestingstructure ,coordinationmode ,competitionre actionandproperty[2~ 9] .ESRcane… 相似文献
92.
Yanqing Ji Hao Ying John Yen Shizhuo Zhu Daniel C. Barth‐Jones Richard E. Miller R. Michael Massanari 《国际智能系统杂志》2007,22(8):827-845
Discovering unknown adverse drug reactions (ADRs) in postmarketing surveillance as early as possible is highly desirable. Nevertheless, current postmarketing surveillance methods largely rely on spontaneous reports that suffer from serious underreporting, latency, and inconsistent reporting. Thus these methods are not ideal for rapidly identifying rare ADRs. The multiagent systems paradigm is an emerging and effective approach to tackling distributed problems, especially when data sources and knowledge are geographically located in different places and coordination and collaboration are necessary for decision making. In this article, we propose an active, multiagent framework for early detection of ADRs by utilizing electronic patient data distributed across many different sources and locations. In this framework, intelligent agents assist a team of experts based on the well‐known human decision‐making model called Recognition‐Primed Decision (RPD). We generalize the RPD model to a fuzzy RPD model and utilize fuzzy logic technology to not only represent, interpret, and compute imprecise and subjective cues that are commonly encountered in the ADR problem but also to retrieve prior experiences by evaluating the extent of matching between the current situation and a past experience. We describe our preliminary multiagent system design and illustrate its potential benefits for assisting expert teams in early detection of previously unknown ADRs. © 2007 Wiley Periodicals, Inc. Int J Int Syst 22: 827–845, 2007. 相似文献
93.
94.
95.
96.
国内3G网络共享问题之研究 总被引:2,自引:0,他引:2
随着国内3G时代的来临,3G网络共享问题越来越受到人们的关注。本文结合国内移动通信的现状,着重分析了3G网络共享的模式及经济效益,论述了3G网络共享的相应策略。 相似文献
97.
Jiayong Cao Yu Zhu Jinsong Wang Wensheng Yin Guanghong Duan 《IEEE transactions on magnetics》2004,40(6):3490-3494
This paper investigates three kinds of permanent-magnet arrays used in planar motors with polarity centers distributed in the lattices of a matrix. The magnetic field of every kind of magnet array is analyzed by analytical methods. First, we give a Laplace equation of magnetic scalar potential and a series of boundary conditions. Then, we derive the analytical expressions of magnet field strength and magnet flux density in the air gap of each kind of magnet array by the method of separation of variables. Finally, we compare the three types of magnet arrays on the basis of the analytical solutions. 相似文献
98.
99.
In this paper, we present a static load balancing method for mapping production rules in an expert system onto processors of a message-passing multicomputer. The method uses simulated annealing to achieve a nearly optimal allocation of production rules onto processor nodes. The approach balances the initial rule distribution to avoid higher communication demand among processor nodes at run time. A formal mapping model is developed and a new cost function is defined for the annealing process. New heuristic swap functions and cooling policies are provided to ensure the quality of the annealing process. A software load balancing package, SIMAL, was implemented on a SUN workstation to carry out the benchmark experiments. The overhead associated with this mapping method is O(m In m), where m is the number of rules in the production system. Two benchmark production systems, Toru-waltz and Tourney, are mapped onto a hypercube computer with 32 nodes. Experimental benchmark results verify the effectiveness of the rule mapping method. The method can be applied for distributed artificial intelligence processing or for the parallel execution of cooperating expert systems on a message-passing multicomputer. 相似文献
100.
分析了并口处于EPP(增强型并行端口)模式时和单片机进行数据交换的原理.介绍了有关EPP的基本特性、信号定义、操作模式及其程序设计方法,设计了基于EPP协议的便携式数据采集系统,给出了技术解决方案,讨论了系统的硬件接口电路和软件编程.方案具有可靠性高、速度快、软硬件设计简捷等优点. 相似文献